smart: store reported symrefs

The protocol has a capability which allows the server to tell us which
refs are symrefs, so we can e.g. know which is the default branch.

This capability is different from the ones we already support, as it's
not setting a flag to true, but requires us to store a list of
refspec-formatted mappings.

This commit does not yet expose the information in the reference
listing.

1 files changed, 56 insertions, 2 deletions

diff --git a/src/transports/smart_protocol.c b/src/transports/smart_protocol.c
index 5dd6bab24..bab0cf113 100644
--- a/src/transports/smart_protocol.c
+++ b/src/transports/smart_protocol.c
@@ -78,7 +78,52 @@ int git_smart__store_refs(transport_smart *t, int flushes)
 	return flush;
 }
 
-int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps)
+static int append_symref(const char **out, git_vector *symrefs, const char *ptr)
+{
+	int error;
+	const char *end;
+	git_buf buf = GIT_BUF_INIT;
+	git_refspec *mapping;
+
+	ptr += strlen(GIT_CAP_SYMREF);
+	if (*ptr != '=')
+		goto on_invalid;
+
+	ptr++;
+	if (!(end = strchr(ptr, ' ')) &&
+	    !(end = strchr(ptr, '\0')))
+		goto on_invalid;
+
+	if ((error = git_buf_put(&buf, ptr, end - ptr)) < 0)
+		return error;
+
+	/* symref mapping has refspec format */
+	mapping = git__malloc(sizeof(git_refspec));
+	GITERR_CHECK_ALLOC(mapping);
+
+	error = git_refspec__parse(mapping, git_buf_cstr(&buf), true);
+	git_buf_free(&buf);
+
+	/* if the error isn't OOM, then it's a parse error; let's use a nicer message */
+	if (error < 0) {
+		if (giterr_last()->klass != GITERR_NOMEMORY)
+			goto on_invalid;
+
+		return error;
+	}
+
+	if ((error = git_vector_insert(symrefs, mapping)) < 0)
+		return error;
+
+	*out = end;
+	return 0;
+
+on_invalid:
+	giterr_set(GITERR_NET, "remote sent invalid symref");
+	return -1;
+}
+
+int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps, git_vector *symrefs)
 {
 	const char *ptr;
 
@@ -141,6 +186,15 @@ int git_smart__detect_caps(git_pkt_ref *pkt, transport_smart_caps *caps)
 			continue;
 		}
 
+		if (!git__prefixcmp(ptr, GIT_CAP_SYMREF)) {
+			int error;
+
+			if ((error = append_symref(&ptr, symrefs, ptr)) < 0)
+				return error;
+
+			continue;
+		}
+
 		/* We don't know this capability, so skip it */
 		ptr = strchr(ptr, ' ');
 	}
@@ -969,7 +1023,7 @@ int git_smart__push(git_transport *transport, git_push *push)
 		if (error < 0)
 			goto done;
 
-		error = git_smart__update_heads(t);
+		error = git_smart__update_heads(t, NULL);
 	}
 
 done: